so with the above combo, we cannot pickup calls on the Jabra Pro 9450, revert back to firmware on T46G phone to 28.81.0.110 and the jabra picks up fine.

3cx is latest version (15.5 sp2) No custom templates. If we bypass the exp40 jabra pro works (so ehs straight into ext port), if we piggy back through the EXP40 no go. If we revert to 28.81.0.110 on T46G no issues.

With new firmware Jabra shows green light on headset base phone icon to indicate it has recieved the pickup signal from the wireless headset.

Staff Member3CX Support

3CX does not test the EHS module and how/if it works with headsets. I seem to remember reading something about this a few weeks ago but for the life of me I kind find the Yealink forum thread I had read it in...
As 3CX does not test this aspect of firmware, I would suggest, if you have not done so already, to also open a discussion on the Yealink forums as well. If they address it in a newer firmware, at some point we will also get that firmware in the 3CX repositories as well.